HVAC DTC Troubleshooting: 3
DTC indicator 3: A Problem in the Air Mix Control Motor Circuit, Linkage, Door, or Motor
1.
Problem verification:

Problem verification
?1.
Turn the ignition switch to LOCK (0) and then back to ON (II).

?2.
Do the Self-Diagnostic Function with the HVAC control unit.

?3.
Check for DTCs.

Is DTC 3 indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure. Check for loose wires or poor connections on the air mix control motor circuit.?
2.
Open wire check (M-HOT DR/M-HOT line):

Open wire check (M-HOT DR/M-HOT line)
?1.
Turn the ignition switch to LOCK (0).

?2.
Disconnect the following connectors.

?3.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Air mix control motor 7P connector: disconnected
Test circuit
M-HOT DR/M-HOT
Test point 1
HVAC control unit 32P connector No. 5 (PNK)
Test point 2
Air mix control motor 7P connector No. 7 (PNK)


Is there continuity?

     
YES
     
     
     
The M-HOT DR/M-HOT wire is not open. Go to step 3.
     
NO
     
     
     
Repair an open in the wire between the HVAC control unit and the air mix control motor.?
3.
Open wire check (M-COOL DR/M-COOL line):

Open wire check (M-COOL DR/M-COOL line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Air mix control motor 7P connector: disconnected
Test circuit
M-COOL DR/M-COOL
Test point 1
HVAC control unit 32P connector No. 6 (LT BLU)
Test point 2
Air mix control motor 7P connector No. 6 (LT BLU)


Is there continuity?

     
YES
     
     
     
The M-COOL DR/M-COOL wire is not open. Go to step 4.
     
NO
     
     
     
Repair an open in the wire between the HVAC control unit and the air mix control motor.?
4.
Shorted wire check (M-HOT DR/M-HOT line):

Shorted wire check (M-HOT DR/M-HOT line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Air mix control motor 7P connector: disconnected
Test circuit
M-HOT DR
Test point 1
HVAC control unit 32P connector No. 5 (PNK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire between the HVAC control unit and the air mix control motor.?
     
NO
     
     
     
The M-HOT DR/M-HOT wire is OK. Go to step 5.
5.
Shorted wire check (M-COOL DR/M-COOL line):

Shorted wire check (M-COOL DR/M-COOL line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Air mix control motor 7P connector: disconnected
Test circuit
M-COOL DR
Test point 1
HVAC control unit 32P connector No. 6 (LT BLU)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire between the HVAC control unit and the air mix control motor.?
     
NO
     
     
     
The M-COOL DR/M-COOL wire is OK. Go to step 6.
6.
Air mix control motor check:

Air mix control motor check
?1.
Test the air mix control motor.

Is the air mix control motor OK?

     
YES
     
     
     
     
NO
     
     
     
Replace the air mix control motor, or repair the air mix control linkage or door.?